The present invention relates to Spectral Doppler ultrasound. Spectral Doppler ultrasound imaging provides an image of velocities (vertical axis) values modulated by energy as a function of time (horizontal axis). This spectrum may be used for studying fluid flow within a patient. By transmitting a plurality of pulses at a single gate location, a Spectral Doppler response is generated in response to received echo signals. The frequency spectrum of the object's motion or flow for a single spatial region is estimated and displayed as a function of time.
Sonographers manually adjust the gate location, gate size, transmit frequency and other Spectral Doppler imaging control parameters in order to acquire a desirable image. Some processes have been proposed for automatic placement of the Spectral Doppler gate. The Spectral Doppler ultrasound imaging provides frequency information for a location, so may not provide spatial information. Spectral information may be provided for different depths along a same scan line. Spectral information for other locations or scan lines is acquired sequentially.
Spatial flow may be represented by Color Doppler imaging. The mean Doppler frequency shift or mean velocity for each of a plurality of spatial locations along multiple scan lines is acquired. The mean velocities are mapped to colors. However, mean velocity, such as derived from the change in frequency for Doppler processing, may not provide sufficient information regarding motion.